You're reading from LLVM Code Generation A deep dive into compiler backend development

Product type Paperback

Published in May 2025

Publisher Packt

ISBN-13 9781837637782

Length 608 pages

Edition 1st Edition

Languages

C++

Tools

LLVM

Concepts

Programming Language

Author (1):

Quentin Colombet

View More author details

Table of Contents (29) Chapters

Preface

1. Getting Started with LLVM

2. Building LLVM and Understanding the Directory Structure FREE CHAPTER

3. Contributing to LLVM

4. Compiler Basics and How They Map to LLVM APIs

5. Writing Your First Optimization

6. Dealing with Pass Managers

7. TableGen – LLVM Swiss Army Knife for Modeling

8. Middle-End: LLVM IR to LLVM IR

9. Understanding LLVM IR

10. Survey of the Existing Passes

11. Introducing Target-Specific Constructs

12. Hands-On Debugging LLVM IR Passes

13. Introduction to the Backend

14. Getting Started with the Backend

15. Getting Started with the Machine Code Layer

16. The Machine Pass Pipeline

17. LLVM IR to Machine IR

18. Getting Started with Instruction Selection

19. Instruction Selection: The IR Building Phase

20. Instruction Selection: The Legalization Phase

21. Instruction Selection: The Selection Phase and Beyond

22. Final Lowering and Optimizations

23. Instruction Scheduling

24. Register Allocation

25. Lowering of the Stack Layout

26. Getting Started with the Assembler

27. Other Books You May Enjoy

28. Index

Adding a new backend in LLVM

In this section, you will learn how to register a new backend in the LLVM build system and plumb the information of that target all the way up to Clang, such that you can enable this target via a Clang invocation.

By the end of this section, you will be able to create a backend that can produce LLVM IR, with the default optimizing and non-optimizing pass pipelines (that is, the O0, O1, and so on options that you regularly use with your favorite compiler toolchain). The optimizations used in these pipelines nevertheless still use the default target information currently.

Let’s dive into the details!

Connecting your target to the build system

Each LLVM backend lives in its own directory under llvm/lib/Target/<MyTarget>, where <MyTarget> is the name of your backend. In our case, we will create an H2BLB directory.

Your first task consists of connecting this new directory to the LLVM build system.

The connection to...